Evaporative crystallizers are used to produce valuable crystalline products, such as tetrasodium ethylenediaminetetraacetic acid (“Na4EDTA”) and disodium EDTA. However, the operation of evaporative crystallizers is often limited in length of reliable operation due to the build-up of fouling deposits inside the evaporative crystallizer vessel. These deposits can interfere with the evaporative crystallizer equipment by partially or fully plugging pumps, transfer lines, and/or heat exchangers, thus requiring that the system frequently be shut down for cleaning
A typical design for a forced circulation evaporative crystallizer includes an outlet flow leaving the evaporative crystallizer at the bottom of the vessel and an inlet on the side of the vessel. Because fouling deposits accumulate at the bottom of the vessel, these deposits exit through the outlet and enter a circulation loop, thus partially or fully plugging the pumps, transfer lines, and/or heat exchangers in that loop. Thus, a need exists for a forced circulation evaporative crystallization system which allows for the accumulation of fouling deposits in order to avoid clogging of the circulation loop.